Re: [PATCH] tests/xfs: test for NULL xattr buffer problem during unlink

[Eryu Guan <eguan@redhat.com>]

On Thu, Oct 12, 2017 at 07:36:27AM -0400, Brian Foster wrote:
> XFS had a bug that resulted in an unexpected NULL buffer during
> unlink of an inode with a multi-level attr fork tree. This occurred
> due to a stale reference to content in a released/reclaimed buffer.
> 
> Use the XFS buffer LRU reference count error injection tag to
> recreate the conditions for the bug. Create a file with a
> multi-level attr fork tree and then unlink it with buffer caching
> disabled.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> ---
> 
> Note that this test depends on a pending[1] XFS error injection tag.
> 
> Brian
> 
> [1] https://marc.info/?l=linux-xfs&m=150765408521029&w=2

I ran this test with above patch applied (v4.14-rc4 based), and kernel
crashed as expected. Then cherry-pick commit f35c5e10c6ed ("xfs: reinit
btree pointer on attr tree inactivation walk") and test passed. So test
looks good to me, just that I added 'dangerous' group and referenced the
fix in commit log and test description.

Thanks for the test!

Eryu